Multiscale Analysis on Coupling Mechanism of Network Structure and Physicochemical Properties of B 2 O 3 ‐Modified ESF Slag

Regulation of electric smelting furnace (ESF) slag composition is an essential strategy to improve the smelting efficiency and product quality of electric smelting furnaces. In this study, a multi‐scale research method was adopted to systematically reveal the action mechanism of B 2 O 3 in CaO–SiO 2 –MgO–Al 2 O 3 –FeO based ESF slag system, and establish the intrinsic structure–performance relationship among sulfide capacity, electrical conductivity, and microstructure of slag. The results reveal that with the increase of B 2 O 3 content, the value of LogC s decreases from −4.15 to −4.33, indicating a reduction in slag sulfide capacity. The activities of FeS and CaS in the system both decline, and the content of free oxygen ions in slag drops from 18.64% to 14.42%. The weakened thermodynamic driving force for desulfurization reaction ultimately deteriorates the desulfurization performance of slag. Molecular dynamics simulation results demonstrate that boron incorporated into the slag structure tends to form highly stable B─O bonds. Silicon always exists dominantly in the form of [SiO 4 ] 4− structural. As the B 2 O 3 content rises from 1% to 10%, [BO n ] gradually transform from three‐dimensional network structures into chain and layered structural. Meanwhile, the (+)/(++) increases from 0.91 to 1.13. Since the field strength of B 3+ is much higher than that of Al 3+ , metal cations preferentially compensate the charge of [BO 4 ] 5− , which promotes the conversion of [AlO 4 ] 5− into [AlO 5 ] 7− and [AlO 6 ] 9− . In the fully liquid region at 1773 K, the electrical conductivity increases from 205.61 to 255.34 mS/cm when B 2 O 3 content increases from 1% to 10%.